Engineers designing circuits in the radio frequency (RF) and microwave range have to search through published and online data sheets, online databases and assorted formats of catalogs in order to find appropriate components to match to specific applications. Engineers have to search through an enormous amount of data to find the best component for a particular requirement, and even the experienced high-frequency design engineer is challenged to understand how some components can fit into a circuit or system better than others.
As used herein, radio frequency is taken to mean the high frequency portion of the electromagnetic spectrum, from at least 3 MHz. Microwave is taken to mean frequencies from at least 300 MHz.
In some design circumstances, a high frequency design engineer will choose to select a component with broader-than-needed general performance characteristics in order to gain improved performance in one or more parameters over a narrower frequency range. For example, rather than simply selecting a double-balanced mixer with RF and intermediate frequency (IF) ranges to translate a desired signal band, the engineer may use broader-band mixers over narrower portions of their range to meet a required linearity specification, or conversion-loss level, or optimum local-oscillator (LO) drive level. This illustrates the complexity of design choices made in selecting high frequency electronic components.
Component searches are increasingly performed over highly distributed computer networks due to the ready availability of the World Wide Web and high-speed Internet access, coupled with ever-improving software and server technology for powering content-rich websites. Online (web-based) catalogs represent one class of computer databases, with online catalogs containing parametric data being a significant subset of those. A further significant subset of this type of catalog allows the user to enter choices for a variety of component parameters to search for at once, to aid in efficient searching for a particular component to be appropriate for use under specific performance conditions. Some catalog database search systems of this type also allow the user to perform a limited range of performance simulations as well.
The majority of online catalogs are based on a server-side system, where the user's machine is not performing any calculations or storing any data. Generally such a system is providing the catalog database function to a large number of users at once and the database is very large, so it is imperative that the system be designed to provide a sufficient quality of data at a speed that the user will find acceptable.
The Yoni-1 catalog database system is an example of an existing online catalog search system containing a considerable body of parametric data for a large number of high frequency electronic components. Users are able to access the catalog through standard web browser software and search for specific components with input variables including frequency range and other electrical performance characteristics, as well as package type. The search output lists the components in the catalog that match the user's search request.
While this type of system offers considerable benefit over simple tabular or graphed listings of devices and their relevant parameters, the search process frequently involves numerous iterations of guessing and refining entered data to gain a match with the component parametric data stored in the database. Further, the selection of high-frequency electronic components requires accurate information about the exact performance of the components under specific conditions of signal input and circuit application.
In another prior art example of a parametric database, a manufacturer of coil springs has an online catalog that allows users to enter a variety of mechanical and dimensional parameters for a desired spring, and the database search output provides a listing of which springs in the catalog will match the specified parameters. This search system has a disadvantage of treating all of the numerous displayed parameters as being of equal relevance, and listing a default choice of “All” for each one. This approach frequently leads to hundreds of springs being shown as search results, or in some cases no springs at all as search results if data for a null combination of parameters is input. In either case it is then up to the user to guess at what has gone wrong and attempt to enter better data for the search parameters, a process that results in the component search requiring numerous iterations.
U.S. Pat. No. 6,334,115 entitled COMPONENT ELECTRONIC CATALOG teaches an electronic component database system intended to aid in selecting and identifying components in a context of circuit design for improved placement during pc board assembly, wherein the stored data includes text-based information about the components, images of the components, mechanical package details and other data relevant to the preparation of automated or semi-automated picking and placing of components. This system is optimized for improving the assembly of components onto pc boards, but has no parameter-based search capabilities for the selection of components for basic circuit design.
U.S. Pat. No. 6,484,169 entitled SELECTION AND ORDERING OF LAMP COMPONENTS teaches an online catalog search system that has a prioritization scheme for a number of component attributes, wherein the user enters a numerical ranking for the importance of each attribute in the context of their specific application. Additionally, if no exact match is achieved with the entered parametric data, data ranges and prioritized attributes, the system informs the user of the no match condition and presents the option of viewing the components in the database that are judged to be closest to the user's criteria. This may lead the user astray, especially if there have already been several frustrating search iterations. There is also no provision for prioritizing the parametric data or data range entries.